Going through the thread, and kinda looks like everything has been said already
But still wanted to add my own experiences with PHA-3.
Bought it about a month ago, and am using it everyday for about 8 hours, sometimes more.
I have the PHA-3ac version since i live in Poland.
I pair it mainly with my AKG K701s with a balanced cable, sometimes with Shure se535 if i feel like isolating myself a bit from surrounding office
Impressions:
PHA-3 + AKG K701 - AMAZING, the headhpnes that i once though are shy in lows suddenly turned into overally great sounding headphones, can't really say anything bad about them anymore.
Ofcourse they are still not basshead type of headphones, but the lows are fantastic now. Just how i love them to be, still very precise, fast, textured, but also deep and ritch.
I recommend this setup with 100% confidence.
Now if anyone tells me k701s are shy in bass, ill simply answer: you are not providing them with enough juice.
Now for the PHA-3 + shure se535 setup.
It sounds great, but then when i hook shures right in to say sansa clip+ it still sounds great.
On PHA-3 i could swear the lows are ritcher, but then i switch back to sansa again, and im not sure anymore
The difference here, if there is one, is very subtle.
Additional things that i noticed, and wanted to share.
When i listen to PHA-3 + K701s very quietly, below certain volume level on PHA, right headphone plays quiter then left one.
I found a solution for it. All you have to do if it happens to you, turn down the volume on whatever you are playing music from, and turn it up on PHA.
Sound becomes perfectly balanced, and i could swear it sounds better too, im guessing because then PHA is actually pushing more power to the headphones.
One time i managed to overheat my PHA.
It was lying on the pillow, and it was a really hot day.
My guess is, even though it doesn't have vents on the bottom, it still uses it's shell as a radiator.
After overheat the unit turned off, i gave it 5 minutes turned back on and it was working again.
Took it off the pillow too
So that's it, not sure if this brings anything new to discussion but there you have it.
I'm very happy to own it